ИСТИНА

One of the most important and actual problems of applied biophysics and nanobioengineering is development of biomedical technologies for efficient targeted delivery and controlled release of drugs in vivo. In this way, it is possible to achieve a significant increase in effectiveness of drug therapy, as well as to minimize side effects of drugs. There are several approaches to creation of controlled delivery and drug release means, for example, it is possible to use microparticles of mesoporous silicon, polymeric capsules and microspheres, as well as biomimetic lipid vesicles- liposomes. The liposome-based approach has advantages like non-toxicity and complete biocompatibility of lipids - in addition to liposomes, lipids are the main structural component of cell membranes. Another advantage of liposomes is ability to vary their size over a wide range, down to submicron. This allows to achieve the best distribution of carriers of the drug directly in the body. A promising approach to development of controlled drug carriers is the approach based on creation of magnetic biomimetic constructions based on nanocomposite liposomes containing magnetic magnetite na-noparticles ( Fe3O4 ) bound to the liposomal membrane [1]. Magnetite particles have magnetic and semiconductor properties and they can pro-vide sensitivity to external electric and magnetic fields. Despite the fact that several approaches can achieve selectivity effect electroporation opening liposomes by external electric field, the use of magnetic fields for controlled release of drugs has the advantage of being completely harmless to human. For experimental studying of the effect of a magnet-ic field on liposomes, we have conducted experiments in which an aqueous suspension of liposomes containing in the internal volume cap-sulated model NaCl solution was incubated in vitro within an hour be-tween the poles of a permanent magnet producing a field intensity of 1.9 kOe. After then conductivity of solution was investigated. As in the case of electrical influences, the method of transmission electron microscopy was also used. Despite the observed jump in the conductivity of the so-lution, the destruction of the vesicles, as in the case of electrical pulse influences, did not occur. The release of the salt solution was explained by the change in the permeability of the lipid bilayer, since under the influence of an external magnetic field the magnetic vesicles were de-formed, their shape was changed from spherical to ellipsoidal. A theo-retical description of the processes is possible by solving the problem of deformation of a layer of a magnetic fluid in an external magnetic field from the position of finding the minimum of the potential energy of the system. Analysis of the formulae obtained by us for the energy of an ellipsoidal magnetic shell indicates that under external magnetic field the minima of the free energy of the magnetic liposome are attained pre-cisely for the shape of an ellipsoid oriented along the major semi-axis along the field, rather than the geoid. The obtained results indicate to the possibility for use of magnetic deformation effect in controlled drug delivery. The work was supported by Russian Foundation for Basic Research (Grant 18-29-02080). [1] G. B. Khomutov, V.P. Kim, Y.A. Koksharov, K.V. Potapenkov, A.A. Parshintsev, E.S. Soldatov, N.N. Usmanov, A.M. Saletsky, A.V. Sybachin, A.A. Yaroslavov, I.V. Taranov, V.A. Cherepenin, and Y.V. Gulyaev. Nano-composite biomimetic vesicles based on interfacial complexes of polyelectro-lytes and colloid magnetic nanoparticles. Colloids and Surfaces A: Physico-chemical and Engineering Aspects, 532:26–35, 2017